197 Chapter 9 Nonstructural Panel Repair Copyright Goodheart-Willcox Co., Inc. Fold Repair, Internal Brace When making this type of repair, it is important to note that the internal brace is the strongest part of the damage. The length of the brace must be restored while repairing the folds. As the brace is lengthened, much of the damage in the folds will snap out. In the example that follows, the internal brace is a collapsed unirail. The panel does not have any direct damage. The folds are gentle, so minimal upset is present. 1. Pulling—Mount the vehicle on a frame machine and tie it down. Attach a clamp to the damaged frame rail and begin to pull out the damage. As the pull on the frame rail begins to restore panel length, the folds begin to move. High areas drop and low areas rise. See Figure 9-51. 2. Leveling—Hammer-off-dolly work will help unlock the folds as the panel length increases. 3. Stretching—Tight folds are upset. Stretch by hammering on the dolly after the panel length is restored. 4. Filing—File across the repair area to identify high areas and low areas. Avoid body lines. Pick and file to restore panel contour. Finishing As previously mentioned, roughing out restores the approximate contour of a panel and finishing completes the repair by restoring the exact contour. The roughing out process must be completed before attempting finishing. Any remaining buckles and stretched or upset areas will cause problems during the finishing process. There are two ways to finish a panel: metal finishing and filling. Metal finishing means the lows and highs will be removed entirely by picking and filing after the roughing process is complete. In filling, body filler is applied to low areas and block sanded to restore the exact shape of the panel. Metal Finishing Metal finishing is the continuation of the pick and file process started during roughing. If metal finishing is done correctly, no filler will be used in the repair. To metal finish a panel, both sides of the panel must be accessible. Metal finishing is most successful on arrowheads in high-crown or double-crown panels without a body line. The arrowheads can be roughed out and the contour restored by metal finishing because the high-crown or double-crown panels are stiff enough to be easily worked. Additionally, high-crown panels are less likely to stretch than low-crown panels. Filler is a better choice for low crown and panels with body lines. During the metal finishing process, every high area must be tapped down and every low area must be tapped up. Continue picking and filing until the panel is smooth and level. Identify high or low areas with a metal file, sanding board, or a grinder. The metal file or grinder disk contacts and marks high areas low areas are not contacted by the file or grinder disk. Use short file strokes on double-crown panels. You can also check for highs and lows with a straightedge or with your hand. If you find a low area that is 1/8″ in diameter or smaller, tap the area up with careful blind picking. One well-placed tap should be all that is required. Try not to raise the low area too much. File or grind to elim- inate high areas that are 1/8″ in diameter or smaller. Low or high areas that are larger than 1/8″ in diameter should be moved with a series of light taps around the perimeter that gradually work toward the center. When lowering a high area, do not cause the adja- cent metal to collapse by tapping too hard. Support adjacent areas with a dolly. As the metal is worked, the picking will tighten the metal, making it less likely to move. Lightly tap the panel to the proper contour rather than tapping a high area down and making a low spot. You must then tap the low area up. Too much tapping up and down will harden the panel, making it unworkable. Filling Filling involves the use of filler to restore panel contour once roughing out is completed. There are two types of filler used on vehicles: body filler and lead filler. Body filler, or plastic filler, is far more common than lead filler. Body filler requires less skill to apply than lead filler. When used properly, body filler is as durable as lead filler, except that lead filler will not crack as body filler does if a filled panel bends or flexes. Restoration shops and a few body shops still use lead filler. Using Body Filler Body filler should not be thicker than 1/8″. Low spots deeper than 1/8″ should be raised before filling. False stretch must be shrunk or eliminated. If a false stretch is popped in and filled, the “oil can” will eventually Goodheart-Willcox Publisher Figure 9-51. Much of the indirect damage on this quarter panel will be pulled out when the frame rail is lengthened. Unibody tie down Unirail damage Hook up Pull